The instant invention relates to exercise apparatus and more particularly to a treadmill having independent side-by-side treads which are individually spring-biased against downward movement during use to effectively provide the aerobic benefits of both walking and climbing.
Treadmill-type walking apparatus have heretofore been known in the art. In this connection, the U.S. Pat. to Speer, Sr. No. 4,204,673; Lee et al No. 4,938,473; and Trulaske No. 5,114,388 represent the closest prior art to the subject invention of which the applicant is aware. The patent to Speer Sr. discloses a treadmill having dual treads which are independently operated to provide a separate control of speed and/or resistance for each leg. The tread platforms are stationary and do not move relative to each other. The patent to Lee et al concerns a treadmill having a trampoline-like surface. The Lee treadmill includes a continuous tread which is supported at the peripheral edges by a plurality of springs. The spring-supported tread is resilient enough to absorb shock and rigid enough to provide a stable exercising surface. There are no rigid supporting surfaces beneath the tread. The Patent to Trulaske discloses a stair exerciser including pivotable stair platforms. The stair platforms reciprocate up and down as the user alternately steps up with each foot.
The instant invention provides a treadmill apparatus having dual treads which are spring biased against downward movement during use. Briefly, the treadmill comprises a frame, and two side-by-side independent treadmills each having a continuous tread and first and second ends. The first and second ends of the two treadmills are each pivotably supported on the frame by pivotable link members which are pivotably connected at a first end thereof to the frame and pivotably connected at a second end thereof to the treadmill body so as to maintain the tread in a generally horizontal disposition. Furthermore, the device includes spring-return hydraulic cylinders which are connected between the link assemblies and the frame. The springs of the cylinders are operable for resiliently supporting the treadmills in a first position above the frame, while the hydraulic portions of the cylinders resist downward movement of the treadmills when weight is placed thereon during walking. The springs of the cylinders are further operative for returning the treadmills to the first position when the weight is removed from the treadmill. The continuous treads may be driven by a mechanical drive means actuated by downward movement of the treadmills, or they may be driven by a motor, or motors, coupled to the respective roller shafts of the treadmills by a belt and pulley system. In use, the operator treads upon the two treadmills in a conventional manner wherein the treadmills alternately move downward and upward as an operator places weight on, and removes weight from each of the treadmills during walking.
Accordingly, among the objects of the instant invention are: the provision of an exercise device which offers the benefits of both walking and climbing; and the provision of a treadmill having dual independent treads which are individually spring-biased against downward movement.
Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.